// SPDX-License-Identifier: GPL-2.0+
/*
 * Spacemit DWMAC platform driver
 *
 * Copyright (C) 2026 Inochi Amaoto <inochiama@gmail.com>
 */

#include <linux/clk.h>
#include <linux/math.h>
#include <linux/module.h>
#include <linux/mfd/syscon.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/regmap.h>

#include "stmmac_platform.h"

/* ctrl register bits */
#define CTRL_PHY_INTF_MODE              GENMASK(4, 3)
#define CTRL_PHY_INTF_RMII              FIELD_PREP(CTRL_PHY_INTF_MODE, 0)
#define CTRL_PHY_INTF_RGMII             FIELD_PREP(CTRL_PHY_INTF_MODE, 1)
#define CTRL_PHY_INTF_MII               FIELD_PREP(CTRL_PHY_INTF_MODE, 3)
#define CTRL_LPI_IRQ_EN                 BIT(9)
#define CTRL_WAKE_IRQ_EN                BIT(12)

/* dline register bits */
#define RGMII_RX_DLINE_EN               BIT(0)
#define RGMII_RX_DLINE_STEP             GENMASK(5, 4)
#define RGMII_RX_DLINE_CODE             GENMASK(15, 8)
#define RGMII_TX_DLINE_EN               BIT(16)
#define RGMII_TX_DLINE_STEP             GENMASK(21, 20)
#define RGMII_TX_DLINE_CODE             GENMASK(31, 24)

#define MAX_DLINE_DELAY_CODE            0xff
#define MAX_WORKED_DELAY                2800
/* Note: the delay step value is at 0.1ps */
#define K3_DELAY_STEP                   367

struct spacmit_dwmac {
        struct regmap *apmu;
        unsigned int ctrl_offset;
        unsigned int dline_offset;
};

static int spacemit_dwmac_set_delay(struct spacmit_dwmac *dwmac,
                                    unsigned int tx_code, unsigned int rx_code)
{
        unsigned int mask, val;

        mask = RGMII_TX_DLINE_STEP | RGMII_TX_DLINE_CODE | RGMII_TX_DLINE_EN |
               RGMII_RX_DLINE_STEP | RGMII_RX_DLINE_CODE | RGMII_RX_DLINE_EN;

        /*
         * Since the delay step provided by config 0 is small enough, and
         * it can cover the range of the valid delay, so there is no needed
         * to use other step config.
         */
        val = FIELD_PREP(RGMII_TX_DLINE_STEP, 0) |
              FIELD_PREP(RGMII_TX_DLINE_CODE, tx_code) | RGMII_TX_DLINE_EN |
              FIELD_PREP(RGMII_RX_DLINE_STEP, 0) |
              FIELD_PREP(RGMII_RX_DLINE_CODE, rx_code) | RGMII_RX_DLINE_EN;

        return regmap_update_bits(dwmac->apmu, dwmac->dline_offset,
                                  mask, val);
}

static int spacemit_dwmac_detected_delay_value(unsigned int delay)
{
        if (delay == 0)
                return 0;

        if (delay > MAX_WORKED_DELAY)
                return -EINVAL;

        /*
         * Note K3 require a specific factor for calculate
         * the delay, in this scenario it is 0.9. So the
         * formula is code * step / 10 * 0.9
         */
        return DIV_ROUND_CLOSEST(delay * 10 * 10, K3_DELAY_STEP * 9);
}

static int spacemit_dwmac_fix_delay(struct spacmit_dwmac *dwmac,
                                    unsigned int tx_delay,
                                    unsigned int rx_delay)
{
        int rx_code;
        int tx_code;

        rx_code = spacemit_dwmac_detected_delay_value(rx_delay);
        if (rx_code < 0)
                return rx_code;

        tx_code = spacemit_dwmac_detected_delay_value(tx_delay);
        if (tx_code < 0)
                return tx_code;

        return spacemit_dwmac_set_delay(dwmac, tx_code, rx_code);
}

static int spacemit_dwmac_update_irq_config(struct spacmit_dwmac *dwmac,
                                            struct stmmac_resources *stmmac_res)
{
        unsigned int val = stmmac_res->wol_irq >= 0 ? CTRL_WAKE_IRQ_EN : 0;
        unsigned int mask = CTRL_WAKE_IRQ_EN;

        return regmap_update_bits(dwmac->apmu, dwmac->ctrl_offset,
                                  mask, val);
}

static void spacemit_get_interfaces(struct stmmac_priv *priv, void *bsp_priv,
                                    unsigned long *interfaces)
{
        __set_bit(PHY_INTERFACE_MODE_MII, interfaces);
        __set_bit(PHY_INTERFACE_MODE_RMII, interfaces);
        phy_interface_set_rgmii(interfaces);
}

static int spacemit_set_phy_intf_sel(void *bsp_priv, u8 phy_intf_sel)
{
        unsigned int mask = CTRL_PHY_INTF_MODE;
        struct spacmit_dwmac *dwmac = bsp_priv;
        unsigned int val = 0;

        switch (phy_intf_sel) {
        case PHY_INTF_SEL_GMII_MII:
                val = CTRL_PHY_INTF_MII;
                break;

        case PHY_INTF_SEL_RMII:
                val = CTRL_PHY_INTF_RMII;
                break;

        case PHY_INTF_SEL_RGMII:
                val = CTRL_PHY_INTF_RGMII;
                break;

        default:
                return -EINVAL;
        }

        return regmap_update_bits(dwmac->apmu, dwmac->ctrl_offset,
                                  mask, val);
}

static int spacemit_dwmac_probe(struct platform_device *pdev)
{
        struct plat_stmmacenet_data *plat_dat;
        struct stmmac_resources stmmac_res;
        struct device *dev = &pdev->dev;
        struct spacmit_dwmac *dwmac;
        unsigned int offset[2];
        struct regmap *apmu;
        struct clk *clk_tx;
        u32 rx_delay = 0;
        u32 tx_delay = 0;
        int ret;

        ret = stmmac_get_platform_resources(pdev, &stmmac_res);
        if (ret)
                return dev_err_probe(dev, ret,
                                     "failed to get platform resources\n");

        dwmac = devm_kzalloc(&pdev->dev, sizeof(*dwmac), GFP_KERNEL);
        if (!dwmac)
                return -ENOMEM;

        plat_dat = devm_stmmac_probe_config_dt(pdev, stmmac_res.mac);
        if (IS_ERR(plat_dat))
                return dev_err_probe(dev, PTR_ERR(plat_dat),
                                     "failed to parse DT parameters\n");

        clk_tx = devm_clk_get_enabled(&pdev->dev, "tx");
        if (IS_ERR(clk_tx))
                return dev_err_probe(&pdev->dev, PTR_ERR(clk_tx),
                                     "failed to get tx clock\n");

        apmu = syscon_regmap_lookup_by_phandle_args(pdev->dev.of_node,
                                                    "spacemit,apmu", 2,
                                                    offset);
        if (IS_ERR(apmu))
                return dev_err_probe(dev, PTR_ERR(apmu),
                                     "Failed to get apmu regmap\n");

        dwmac->apmu = apmu;
        dwmac->ctrl_offset = offset[0];
        dwmac->dline_offset = offset[1];

        ret = spacemit_dwmac_update_irq_config(dwmac, &stmmac_res);
        if (ret)
                return dev_err_probe(dev, ret, "Failed to configure irq config\n");

        of_property_read_u32(pdev->dev.of_node, "tx-internal-delay-ps",
                             &tx_delay);
        of_property_read_u32(pdev->dev.of_node, "rx-internal-delay-ps",
                             &rx_delay);

        plat_dat->get_interfaces = spacemit_get_interfaces;
        plat_dat->set_phy_intf_sel = spacemit_set_phy_intf_sel;
        plat_dat->bsp_priv = dwmac;

        ret = spacemit_dwmac_fix_delay(dwmac, tx_delay, rx_delay);
        if (ret)
                return dev_err_probe(dev, ret, "Failed to configure delay\n");

        return stmmac_dvr_probe(dev, plat_dat, &stmmac_res);
}

static const struct of_device_id spacemit_dwmac_match[] = {
        { .compatible = "spacemit,k3-dwmac" },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, spacemit_dwmac_match);

static struct platform_driver spacemit_dwmac_driver = {
        .probe  = spacemit_dwmac_probe,
        .remove = stmmac_pltfr_remove,
        .driver = {
                .name = "spacemit-dwmac",
                .pm = &stmmac_pltfr_pm_ops,
                .of_match_table = spacemit_dwmac_match,
        },
};
module_platform_driver(spacemit_dwmac_driver);

MODULE_AUTHOR("Inochi Amaoto <inochiama@gmail.com>");
MODULE_DESCRIPTION("Spacemit DWMAC platform driver");
MODULE_LICENSE("GPL");